This is what makes them appear to look global when in fact they are specific to each module. As you can see, both approaches - requiring a .js and requiring a .json file - result in the same outcome: exposure of a JavaScript hash of configuration information. We can also create a find-me folder under node_modules and place an index.js file in there. 1. const aweFunky = require("/js/awefunky.js"); The require statement was used for the last thousand years and people seemed to be happy about them. Let’s say we would like to scan a file from the file system. Requiring JSON files is useful if, for example, everything you need to manage in that file is some static configuration values, or some values that you periodically read from an external source. As such, I wanted to put together a quick demo. Node modules have a one-to-one relation with files on the file-system. We can, for example, see the index.js module fully loaded if we print its module object on the next cycle of the event loop using a setImmediate call: Note how in this delayed console.log output both lib/util.js and index.js are fully loaded. We’ve seen the resolve property, which is a function that performs only the resolving step of the require process. I am the co-founder and a principal engineer at InVision App, Inc Such is the power of the require() method in Node.js. Donations to freeCodeCamp go toward our education initiatives, and help pay for servers, services, and staff. We also have thousands of freeCodeCamp study groups around the world. Tweet a thanks, Learn to code for free. As you can see, it worked perfectly. We need a way to determine if the file is being run as a stand-alone script or if it is being required by other scripts. That’s it. In a browser, when we declare a variable in a script like this: That answer variable will be globally available in all scripts after the script that defined it. The require() function, in Node.js, can read in both .js and .json files. Then we have the require/module objects, both of which are instances that are associated with the index.js file that we’re executing. 3000:... var request = require('request-json');var client = request.createClient('http://localhost:4000/'); ... 4000:app.get('/Teste2', function(req, res){ var jsonmsg= {"MSg":"teste"}; res.json(jsonmsg);}). When present, it specifies that the element must be filled out before submitting the form. Let me introduce you to the module object. Moreover, since every module gets wrapped in a function, we can actually access that function’s arguments with the arguments keyword: The first argument is the exports object, which starts empty. Assuming the required module will export the printInFrame function and we can just call it: To print the header “Hey” in a frame of 5 stars. to do isolated scripting tasks, providing a bit of interactivity to your web pages where needed, so large scripts were generally not needed. Now, let's create another file - config.json - which contains truly static configuration data: Ok, now let's try to read in both of these files using the require() method and log the result out to see what Node.js is doing: When we run this code, we get the following terminal output, ben$ node explicit-ext.js When we define a variable in one module, the other modules in the program will not have access to that variable. is now listed as the parent for the lib/util module. The Node documentation site has a sample addon file which is written in C++. 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